<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>

  <style>
    .box {
      width: 100px;
      height: 100px;
      border-radius: 50%;
      border: 1px solid red;
      background-color: red;
      /* 过度动画=>属性 */
      /* transition:   width 1s linear 0s, height 1s linear 0s; */
      transition: all 2s linear;
    }

    .box:hover {
      width: 200px;
      height: 200px;
      border-radius: 0%;
      background-color: blue;
      opacity: 0.1;
    }
  </style>

  <body>
    <div class="box"></div>
    <div class="boxInner"></div>
  </body>
</html>
